# Copyright (c) 2016 Google Inc. (under http://www.apache.org/licenses/LICENSE-2.0)
def h1(a:a1) -> r1 : ...

def h2(a:a2, b:b2) -> r2: ...

def h3(a:a3,) -> r3: ...

def h4(a:a4 #
     , ) -> r4: ...

